Corbelworks · Contractor Operations

Late Payment Interest & Prompt-Pay Rules for Contractors — Arizona

Disclaimer: The legal information provided in this article regarding prompt payment statutes and maximum interest rates in Arizona is accurate to the best of our knowledge as of August 10, 2026. Laws change frequently; always consult with a qualified local construction attorney before enforcing late fees or drafting contract clauses.

When a client in Arizona drags their feet on a progress payment, you act as an unsecured lender for their project. Every day that invoice sits unpaid past its net terms, your cash bleeds out as carrying costs. Understanding the state's prompt-payment statutes and allowable interest rates is fundamental for protecting your operating margins.

Prompt Payment Rules in Arizona

Private Construction Projects

Private owners must pay within 7 days of billing certification (usually 21 days to certify, so 28 total). Primes pay subs within 7 days.

Maximum Allowable Interest (Private): 1.5% per month (18% annually)

Public Construction Projects

Public owners must pay within 14 days of certification. Primes pay subs within 7 days.

Maximum Allowable Interest (Public): 1% per month (12% annually)

The Cost of Floating Invoices (A Arizona Example)

Consider a scenario where you are owed $25000 on a completed milestone, and the payment is 30 days past the statutory deadline or your contract terms. Based on common statutory limits, the carrying cost you might legally be entitled to recover can accumulate quickly. For example, if you applied an appropriate rate under Arizona law, the delay could cost the client an additional $375.00 in interest.

You aren't just slapping an arbitrary fee on the invoice; you are recovering the actual financial damage caused by the delay, backed by state legislation.

Enforcing Fees Operationally

To protect yourself, your master service agreement must include a clear, unambiguous clause regarding late payments. A recommended practice is to cite the maximum allowable rate under Arizona law as a cap, defaulting to the statutory rate if your contract rate is deemed usurious.

Interest terms must be consistently communicated. They should be printed on every single invoice you send, typically near the total due. Using a clear internal standard operating procedure (SOP) ensures these rules are applied objectively, removing emotion from the collections process.

Stop guessing on your math and state laws. Calculate exact costs with our free tool: Late Invoice Interest & Carrying Cost Calculator

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